import java.util.Scanner;

public class d068_該減肥了 {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		String input, output;
		int weight;
		
		while(sc.hasNext()) {
			input = sc.nextLine();
			weight = Integer.parseInt(input);
			
			while(weight > 50) {
				weight -= 1;
				break;
			}
			
			output = Integer.toString(weight);
			
			System.out.println(output);
		}
	}
	
}